Current research indicates that a significant subset of children who are treated for cancer experience difficulty in post-treatment psychosocial adjustment, including symptoms of post-traumatic stress, anxiety and depression. Unfortunately, to date there has been limited success in predicting which children will be most negatively affected by having cancer and undergoing necessary but often painful treatments. The current study is designed to test the hypothesis that children's post-treatment adjustment is related to both their emotional regulation abilities and to parenting processes that affect how they process and cope with strong negative emotions. Vagal tone, a physiological index of emotion regulation, has been shown to buffer children from negative psychological effects of stressors in their environment. However, up to this point, no research has investigated whether vagal tone is related to psychosocial functioning in cancer survivors. The proposed study will use a multi-method, multi-informant, cross-sectional design to test the relationship between vagal tone and adjustment in 150 children, half of whom will be survivors of Acute Lymphocytic Leukemia. Additionally, how parents think about emotions and help their children manage their emotions - their "meta-emotion philosophy" - will be examined as a potential buffer in the relationship between cancer treatment and range of negative psychosocial outcomes. Understanding the relationship between emotion regulation abilities and adjustment following cancer treatment can help build new and effective empirically based interventions that focus on (1) teaching children how to physiologically self-soothe when distressed and (2) teaching parents to help children manage their emotions.